Circuit breaker with improved terminal means



p 1966 F. L. GELZHEISER 3,271,549

CIRCUIT BREAKER WITH IMPROVED TERMINAL MEANS Filed Dec. 30, 1963 2Sheets-Sheet l NONI! Sept. 6, 1966 F. L. GELZHEISER 2 Sheets-Sheet 2Filed Dec.

F i INVENTOR Francis L. Gelzheiiser Fig] P43 14:

ATTORNEY United States Patent 3,271,549 CIRCUIT BREAKER WITH IMPROVEDTEAL MEANS Francis L. Gelzheiser, Fairiield, Conn, assignor toWestinghouse Electric Corporation, Pittsburgh, Pa., a corporation ofPennsylvania Filed Dec. 30, 1963, Ser. No. 334,089 12 Claims. (Cl.200170) This invention relates generally to circuit breakers and moreparticularly to circuit breakers of the type comprising two circuitbreaker mechanisms constructed for removable connection to a common stabconductor.

In order to provide more compact and less expensive load centers,certain types of circuit breakers are constructed as double-type circuitbreakers comprising two circuit breaker mechanisms with two separateline terminals that are constructed for removable connection to a commonstab conductor. This type of circuit breaker is disclosed in the patentto Earl Bullis, Jr, Patent No. 3,200,217, issued August 10, 1965. In theaforementioned patent, there is disclosed a double-type circuit breakercomprising two separate line terminals that are so seated in theinsulating housing that when the circuit breaker is plugged onto a stabconductor the terminals are spread apart and each terminal is flexedbetween the insulating housing and the stab conductor to effect contactpressure. This arrangement is entirely satisfactory and effective forthe lower rated circuit breakers such, for example, as the circuitbreakers that are rated at 15 and 20 amperes. When this type of circuitbreaker is up rated to, for example, 40 amperes and above, the switchingand short circuit heating becomes excessive and tends to cause arelieving of the line terminals and also a relieving of the insulatinghousing in which the line terminals are seated. When this occurs, thecontact pressure between the line terminals and the stab conductorweakens and further heating results to further weaken the contactpressure. Thus, it is desirable to provide biasing means for maintainingadequate contact pressure between each of the separate line terminalsand the stab conductor, which biasing means operates independently ofthe molded insulating housing in order to effect the bias.

Accordingly, an object of this invention is to provide an improveddouble-type circuit breaker comprising two separate line terminals thatare constructed to be connected to a conducting stab with improved meansfor maintaining contact pressure between the line terminals and theconducting stab.

Another object of this invention is to provide an improved double-typecircuit breaker comprising two separate line terminals and biasing meansfor providing contact pressure between the line terminals and aconducting stab, which biasing means operates independently of thecircuit-breaker housing in order to provide the contact pressure.

When a double-type circuit breaker is plugged onto a conducting stab, itcan sometimes occur that the stab is not in good alignment with thecircuit breaker. It is desirable, therefore, to have a construction thatwill enable automatic alignment between each of the separate terminalsand the conducting stab.

Thus, another object of this invention is to provide an improveddouble-type circuit breaker comprising two separate line terminals andbiasing means that operates independently of the circuit-breaker housingfor effecting contact pressure between each of the line terminals andthe conducting stab with means providing for contact alignment when theconducting stab and the circuit breaker are not properly aligned.

A more general object of this invention is to provide an improveddouble-type circuit breaker that is dependable, relatively inexpensive,and relatively easy to manufacture and assemble.

The novel features that are considered characteristic of this inventionare set forth in particular in the appended claims. The invention, bothas to structure and operation, together with additional objects andadvantages thereof, will be best understood from the following detaileddescription when read in conjunction with the accompanying drawings, inwhich:

FIGURE 1 is a side sectional view taken generally along the line II ofFIG. 3;

FIG. 2 is a view similar to FIG. 1; except that the parts are shown inthe tripped position;

FIG. 3 is an end view, on a smaller scale relative to FIGS. 1 and 2, ofthe double-type circuit breaker;

FIG. 4 is an exploded perspective view, on an enlarged scale relative toFIGS. 1, 2 and 3, of the two separate line terminals and the biasingmeans seen in FIGS. 1, 2 and 3;

FIGS. 5 and 6 are side and end elevational views respectively of theline terminals and biasing means of FIG. 4 in the assembled position;

FIG. 7 is a plan view of the blank from which the biasing member seen inFIGS. 4-6 is formed; and

FIG. 8 is a bottom view of the biasing member formed from the blank seenin FIG. 7.

The general operation and certain parts of the circuit breaker disclosedherein are described more specifically in the above-mentioned patent toEarl Bullis, Jr., Patent No. 3,200,217.

Referring to FIG. .3 of the drawings, a double-type circuit breaker 9 isshown therein comprising an insulating housing that is composed of twomolded insulating parts, 11 and 13, forming two compartments. Each ofthe parts 11 and 13 comprises a back portion molded integral with foursides forming an open front. The open front of the part 11 is covered bythe back portion of the part 13 which serves as an insulating barrierbetween the two compartments and the open front of the part 13 iscovered by a molded insulating cover 15. The three molded insulatingportions 11, 13 and 15 of the housing are held rigidly together by threerivets 18 (FIGS. 1 and 2).

The housing parts 11, 13 and 15 form two insulating compartments housingtwo circuit breaker mechanisms which are identical in construction andoperation, each of which mechanisms operates independently of the other.For this reason, only the mechanism enclosed by the housing part 11 willbe specifically described, it being understood that, unless otherwisementioned, the description applies to both of the mechanisms of thedoubletype circuit breaker.

Referring to FIG. 1, the circuit-breaker mechanism, which is enclosed bythe housing part 11 and the back portion -of the housing part 13,comprises a stationary contact 21, a movable contact 23, a supportingmetal frame 25, an operating mechanism 27 and a trip device 29.

The stationary contact 21 is Welded, or otherwise rigidly secured, to aline terminal 31 that will be hereinafter more specifically described.The stationary contact 21 for the circuit breaker mechanism that ishoused in the housing part 13 (FIG. 3) is welded, or otherwise rigidlysecured, to a line terminal 37 that is similar to the line terminal 31except that it is constructed to be connected to a different side of agenerally rigid and fiat conducting stab 38 that the terminals 31 and 37can be plugged onto. The line terminals 31 and 37 are independent inthat each is a part of a separate independently functioningcircuit-breaker mechanism and each separately electrically feeds theseparate circuit-breaker mechanism in the associated compartment.

Referring to FIGS. 1 and 2, the stationary contact 21 cooperates withthe movable contact 23 that is welded or otherwise rigidly secured to agenerally C-shaped contact arm or switch arm 41. A hearing member 42 isprovided with a slot that is complementary with a slot in the upper partof the contact arm 41 and the bearing is provided with two upper legportions that fit into suitable slots in a molded insulating operatingmember 47. The bearing 42 transmits motion from the operating member 47to the movable contact arm 41 when the breaker is manually operated,and, as will be hereinafter explained, from the movable contact arm 41to the operating member 47 when the breaker is tripped automatically inresponse to an overload current condition.

The operating member 47 is a molded insulating member having an arcuatetrunnion 51 molded at each side thereof. The trunnions 51 fit androtatably ride on two arcuate surfaces 55 that are formed on themetallic supporting frame 25. The operating member 47 is supportedbetween the surfaces 55 of the frame 25 and the bearing 42 which issupported by the contact arm 41. The operating member 47 has a handlepart 59 molded integrally therewith, which handle part extends throughan opening 61 (FIG. 2) in the insulating housing to permit manualoperation of the circuit breaker. Arcuate surfaces 63 on opposite sidesof the handle 59 substantially close the opening 61 in all positions ofthe operating member 47.

The frame 25 supports an insulating pivot 65. A metallic trip member 79is pivotally supported at one end 77 thereof on the pivot 65. The otherend 82 of the trip member 79 has a latch surface 83 that rests (FIG. 1)on a ledge 85 (FIG. 2) on an armature 86 to support the trip member inthe latched position seen in FIG. 1. The armature 86 is part of the tripdevice 29 which will be hereinafter specifically described. The ends 77and 82 of the trip member 79 are offset and disposed in a plane that isparallel to the plane in which the main body portion of the trip member79 is disposed. An overcenter spring 88 (FIGS. 1 and 2) is connected,under tension, at one end in an opening in the contact arm 41 and at theother end in a slot in a projection 93 extending from the trip member79.

The movable contact arm 41 is connected by means of a flexible conductor95 to the free end of a bimetal 97 that is attached at its other end toa load terminal conductor 99. A load terminal connecting screw 100,which is externally accessible, is provided at the outer end of theconductor 99 to enable connection of the circuit breaker in an electriccircuit. The load terminal conductor 99 is welded or otherwise attachedto a projection 101, extending out from the supporting frame 25. Theterminal conductor 99 is given additional support by being looped overand welded to another projection 103 extending out from the supportingframe 25. Thus, the load terminal conductor is rigidly held in placewithin the housing part 11.

The closed electric circuit through the circuit-breaker mechanismextends from the line terminal 31 (FIG. 1) through the stationary andmovable contacts 21, 23, the contact arm 41, the flexible conductor 95,the bimetal member 97, the load terminal conductor 99, to a conductingwire that would be electrically connected to the conductor 99 by meansof the screw 100 when the circuit breaker is in operating position.Since the movable contact arm 41 extends downward from its pivot, theare is established adjacent the bottom of the housing in an arc chute111, one end of which is connected by a vent passage 113 to an openingin the end of the housing beneath the load terminal screw 100.

The circuit breaker is manually operated to open and close the contacts21, 23 by operation of the insulating handle 59. Movement of the handle59 clockwise from the full-line on position (FIG. 1) to the o positionin which it is shown in dot-and-dash lines, carries the upper end of thecontact arm 41 to the left of the line of action of the spring 88whereupon the spring acts to move the contact arm 41, with a snapaction, to the open position shown partially in dot-and-dash lines inFIG. 1. A projection 109, molded integral with the housing part 11, actsas a stop to limit opening movement of the contact arm 41. Movement ofthe operating handle 59 in a counterclockwise direction from the off tothe on position moves the upper end of the movable contact arm 41 to theright of the line of action of the spring 88 whereupon the springoperates to move the contact arm to the closed position seen in FIG. 1.Movement of the handle 59 in both directions is limited by the surfaces115 (FIG. 1) which strike the frame 25 at the opposite sides of thepivot 51.

The trip device 29 is provided to effect automatic opening of thecircuit breaker upon the occurrence of overload current conditions. Thetrip device 29 comprises the magnetic armature 86, the bimetal 97, a U-shaped magnetic member 117 that is secured to the bimetal 97 with thefree ends thereof facing in the direction of the magnetic member 86 anda spring 119. The upper end of the bimetal 97 is welded or otherwisesuitably secured to the terminal conductor 99 which is secured to theprojection 101 on the metal frame 25. The flexible conductor 95 iswelded or otherwise suitably secured to the lower or free end of thebimetal 97, and it electrically connects the bimetal 97 with the movablecontact arm 41. The armature 86 is movably mounted on the bimetal 97 bymeans of a spring 119 that is sesured at the lower end thereof to thebimetal 97 and at the upper end thereof -to the armature 86.

Upon the occurrence of an overload current below a predetermined value,the bimetal element 97 is heated, and when it is heated a predeterminedamount, it deflects, with a time delay, to the right as seen in FIG. 1to effect a thermal tripping ope-ration. The armature 86, which issupported on the bimetal 97 by means of the spring 1 19, is carried tothe right with the bimetal to release the trip member 79. When the tripmember 79 is released, the spring 88 acts to rotate the trip memberclockwise about the pivot to the tripped position seen in FIG. 2. Duringthis movement, the line of action of the spring 88 moves to the right ofthe pivot 42 of the contact arm 41 whereupon the spring biases thecontact arm in an opening direction and moves the contact arm so thatthe line of action of the force exerted by the spring on the operatingmember 47 shifts across the pivot 51 whereupon the spring 88 actuatesboth the contact arm 41 and the operating member 47 to the trippedposition in which these parts are shown in FIG. 2. In order to provide avisual indication that the breaker has been automatically tripped open,movement of the operating member 47 is stopped in an intermediateposition (FIG. 2) when a projection 127, molded integral with theoperating member 47, strikes the projection 93 which extends from thetrip member 79. The parts are shown in the tripped open position in FIG.2. The circuit breaker is trip-free in that the breaker will trip uponthe occurrence of an overload even if the handle 59 is held in the on orclosed position.

Before the contacts can be closed following an automatic openingoperation, it is necessary to reset and relatch the mechanism. This isaccomplished by moving the operating handle 59 clockwise from thetripped open position (FIG. 2) to the full off position. During thismovement, due to the engagement of the projection 127 of the operatingmember 47 with the projection 93 of the trip member 79, the trip memberis moved counterclockwise about the pivot 65 until the latch point 83 isagainst supported in the latched position on the ledge of the armature86. Thereafter, the circuit breaker can again be manually operated inthe same manner hereinbefore described.

The circuit breaker is magnetically tripped automatically andinstantaneously in response to overload currents above the predeterminedvalue. Upon the flow of current through the bimetal 97, a magnetic flux,which is induced around the binmetal, takes the path of least reluctancethrough the magnet 117, across an air gap and through the armature 86.When an overload current above the predetermined value occurs, the pullof the magnetic \flux is of such strength that the armature 86 isattracted to the magnet 117 whereupon the spring 119 flexes permittingthe armature to move relative to the bimetal 97 to the right. Thismovement releases the trip member 79, and the contacts are opened in thesame manner hereinbefore described with respect to the thermal trippingoperation.

Referring to FIGS. 46, the two separate line terminals 31 and 37, forthe two separate circuit-breaker mechanisms, are biased toward eachother by means of a one-piece spring steel biasing and supporting member12 5. The member 125 is formed from a generally flat sheet-metal blank127 (FIG. 7) that is folded over at 129 to provide an upper part 131 anda lower part 133.

Referring to FIG. 7, the upper part 131 is folded over at 137 to providea flaring part 139 (FIGS. 4 and 5). The lower part 133 (FIG. 7) is bentover at 141 to provide a biasing part 143 (FIGS. 4-6). The lower part133 (FIG. 7) is also bent-over at 145 to provide another biasing part 147 (FIGS. 4-6). As is seen in FIG. 8, the biasing parts 143 and 147 areon opposite sides of a slot 149 in the lower part 133.

Each of the terminal members 31 and 37 (FIGS. 4-6) comprises a generallyresilient conducting member comprising a generally flat planar contactpart 15-1 and a generally flat planar support part 153 that is bent overto extend generally normal to the contact part 151. The contact parts151 are bent at the lower ends thereof to .form flaring parts 155. Eachof the terminal members 31 and 37 is bent over to provide a generallyflat planar contact carrying part 157 to which the associated stationarycontact 21 is welded or otherwise rigidly secured. As is seen in FIGS.46, the plane of the contact carrying part 157 is generally normal tothe planes of both the support part 153 and the contact part 151.

The member 125 is a hardened and treated spring steel member with a veryhigh annealing temperature so that it is unaffected by any of thepossible temperature changes that will arise in the circuit breaker.

Referring to FIG. 4, the member 125 is formed with a dimension, at 158(IFIG. 4), between the upper part 131 and the lower part 133 that isless than the thickness of the supporting parts 153 of the terminals 31and 37. Thus, when the parts are assembled, there is an interference fitbetween the supporting parts 153 of the line terminals 31 and 37, andthe folds 13 1 and 133 of the member 125. As is seen in FIGS. 5 and 6,when the parts are assembled, the two biasing parts 143 and 147 of themember 125, which are staggered (FIG. 8), engage the outer sides of thecontact parts 151 of the separate terminals 31 and 37 to bias thecontact parts 151 of the terminals 31 and 37 toward each other. Thus,when the circuit breaker 9 (FIG. 3) is plugged onto the conducting stab38, the line terminal end thereof is forced onto the stab and thebiasing parts 143, 147 (FIG. 6) of the member 125 bias the separateterminals 31 and 37 against the conducting stab 38 to provide contactpressure between the terminals and the conducting stab. The spacing andformation of these parts relative to the conducting stab is such thatthe flat contact parts 151 will be generally parallel engaging theopposite parallel flat surfaces of the stab 38 in the connectedposition.

As is seen in FIG. 3, there is an opening at the inside lower corner ofeach of the insulating housing parts 11 and 13 to provide a generalopening or cavity 161 in the insulating housing to thereby provideaccess for the conducting stab 38. The members 31, 37, 125 are placed inthe cavity 161 during the assembly of the housing parts 11, 13, 15 andthey are held in position by engagement thereof with the wall portionsof the cavity 161. As is seen in FIGS. 1 and 2, when the circuit breakeris moved into the connected position, the upper part of the member willengage the upper surface of the insulating housing parts 11 and 13 tolimit upward movement of the members 31, 37, 125 to thereby permit themembers 31 and 37 to be connected to the conducting stab 38 ('FIG. 3) byforcing the line end of the circuit breaker 9 onto the stab 38.

For some applications only one circuit-breaker mechanism is utilized inonly one compartment and the other compartment is empty. In these cases,only one of the separate terminals 31 or 37 will be necessary to conductcurrent to the one mechanism, although both of the terminals 31 and 37can be used with the spring 125 to provide the plugin or clip-on typeconnection with the stab 38.

As is seen in FIGS. 1 and 2, the cavity 161 in the housing is of such asize that the members 31, 37, 125 can move to a limited extent so thatthe members can adjust to the position of the conducting stab 33 if thestab is not in alignment with the circuit breaker 9 when the circuitbreaker is moved into the connected position. Thus, if the contactconducting stab 38 is not absolutely perpendicular to its generalmounting surface so that it may not be in alignment with the circuitbreaker, the members 31, 37, 125 can adjust or move to a limited extentin the cavity 161 so that the contact parts 151 of the terminals 31 and37 can make good contact with the generally parallel fiat surfaces ofthe stab 38. This is also true if the stab 38 happens to be rotatedslightly about the vertical axis 1 69 (FIG. 3). In this case, themembers 31, 37, 125 can rotate to a limited extent within the opening161 to adjust for proper contact alignment and engagement.

The biasing member 125 does not cooperate with the insulating housing inorder to provide the biasing force for contact pressure between theterminals 31, 37 and the conducting stab 3 8. Thus, if the insulatinghousing is relieved to some extent because of heat that may be generatedin the circuit-breaker mechanism under excessive switching and shortcircuit conditions, this relief of the insulating housing will notaffect the contact pressure between the terminals 31, 37 and theconducting stab 38.

While the invention has been disclosed in accordance with the provisionsof the patent statutes, it is to be understood that various changes inthe structural details and arrangement of parts may be made withoutdeparting from some of the essential features of the invention. It isdesired, therefore, that the language of the appended claims be given asreasonably broad an interpretation as is permitted by the prior art.

I claim as my invention:

1. In combination, two adjacent insulating compartments, acircuit-breaker mechanism supported in each of said compartments, eachof said mechanisms comprising a stationary contact and a movable contactcooperable with the stationary contact to open and close an electriccircuit, said mechanisms being independently operable, a separateexternally accessible load terminal supported at one end of each of saidcompartments, a separate line terminal disposed at the other end of eachof said compartments, and a separate unitary spring member biasing saidseparate line terminals toward each other whereby when said separateline terminals are connected to a common conducting stab said separateunitary spring member provides contact pressure between each of saidseparate line terminals and the common conducting stab.

2. A double-type circuit breaker comprising an insulating housing, apair of separate circuit-breaker mechanisms disposed within saidhousing, said housing having a cavity therein at one end thereof, a pairof separate line terminals disposed generally within said cavity andeach electrically connected with a different one of said mechanisms, anda separate unitary spring member biasing said separate line terminalstoward each other whereby when said circuit breaker is plugged onto acommon conducting stab at said one end said separate unitary springmember provides contact pressure between each of said separate lineterminals and the conducting stab.

3. A double-type circuit breaker comprising an insulating housingcomprising two adjacent insulating compartments, a separatecircuit-breaker mechanism supported in each of said compartments, eachof said mechanisms comprising a pair of contacts relatively movable toopen and close an electric circuit, said insulating housing having arecess therein at one end thereof, two separate terminal members and aseparate spring member disposed generally within said recess, each ofsaid separate terminal members being connected in electrical series witha different one of said pair of contacts, said separate springmembersupporting said separate terminal members such that said separate springmember and said separate terminal members are movable as a unit withinthe confines of said recess, and said separate spring member functioningindependently of said housing to bias said separate terminal memberstoward each other.

4. A double-type circuit breaker comprising an insulating housing, saidinsulating housing comprising two adjacent insulating compartments, aseparate circuit-breaker mechanism supported in each of saidcompartments, each of said mechanisms comprising a pair of contactsrelatively movable to open and close an electric circuit, saidinsulating housing having a cavity therein at one end thereof, twoseparate line terminals and a separate spring member disposed generallywithin said cavity, each of said separate line terminals being connectedin electrical series with a different one of said pairs of contacts,said separate spring member supporting said separate line terminals suchthat said separate spring member and said separate line terminals aremovable as a unit within the confines of said cavity, said separatespring member and said separate line terminals being supported forlimited universal movement within the confines of said cavity, and saidseparate spring member functioning independently of said housing to biassaid separate line terminals toward each other.

5. A double-type circuit breaker comprising an insulating housing, saidinsulating housing comprising two adjacent insulating compartments, aseparate circuitbreaker mechanism supported in each of saidcompartments, each of said mechanisms comprising a pair of contactsrelatively movable to open and close an electric circuit, saidinsulating housing having a recess therein at one end thereof, twoseparate line terminals and a spring member disposed generally withinsaid recess, means connecting each of said separate line terminals inelectrical series with a different one of said pairs of contacts, eachof said two separate line terminals comprising a generally flat planarsupport part and a generally fiat planar contact part extendinggenerally normal to the plane of the support part, a spring memberengaging the opposite fiat surfaces of both of the support parts of saidtwo separate line terminals to support said two separate line terminals,and said spring member comprising biasing means operating independentlyof said insulating housing to bias said contact parts toward each other.

'6. A double-type circuit breaker comprising an insulating housingcomprising two adjacent insulating compartments, a separatecircuit-breaker mechanism supported in each of said compartments, eachof said mechanisms comprising a pair of contacts relatively movable toopen and close an electric circuit, said insulating housing having acavity therein at one end thereof, two separate terminal members and aspring member disposed generally within said cavity, means connectingeach of said two separate terminal members in electrical series -with adifferent one of said pairs of contacts, each of said two separateterminal members comprising a generally flat planar support part and agenerally flat planar contact part extending generally normal to theplane of the support part, a unitary spring member engaging the oppositefiat surfaces of both of the support parts of said two separate terminalmembers to support said two separate terminal members, said unitaryspring member comprising two biasing parts biasing said two contactparts toward each other, and said two separate terminal members andspring member being supported for limited unitary movement within theconfines of said cavity whereby said contact parts can align with acon-ducting stab when said two separate terminal members are pluggedonto the common conducting stab.

7. A double-type circuit breaker comprising an insulating housingcomprising two adjacent insulating compartments, a separatecircuit-breaker mechanism supported in each of said compartments, eachof said mechanisms comprising a pair of contacts relatively movable toopen and close an electric circuit, said insulating housing having arecess therein at one end thereof, two separate line terminals and aspring member disposed generally within said recess, each of said twoseparate line terminals comprising a generally flat planar support partand a generally flat planar contact part extending generally normal tothe plane of the support part, a unitary spring member comprising afolded over sheet-metal type member engaging the opposite flat surfacesof both of the support parts of said two separate line terminals betweenthe folded-over parts thereof to support said two separate lineterminals, said spring member comprising two biasing parts bent-overfrom one of the folds thereof and biasing said two contact parts towardeach other whereby when said two separate line terminals are connectedto a common generally rigid conducting stab said two biasing partsprovide contact pressure between each of said two separate lineterminals and the conducting stab.

8. A double-type circuit breaker comprising an insulating housingcomprising two adjacent insulating compartments, a separatecircuit-breaker mechanism supported in each of said compartments, eachof said mechanisms comprising a pair of contacts relatively movable toopen and close an electric circuit, said insulating housing having arecess therein at one end thereof, two separate line terminals and aspring member disposed generally within said recess, each of said twoseparate line terminals comprising a generally flat planar support partand a generally flat planar contact part extending generally normal tothe plane of the support part, a unitary spring member comprising afolded over sheet-metal type member engaging the opposite fiat surfacesof both of the support parts of said two separate line terminals betweenthe folded-over parts thereof to support said two separate lineterminals, said spring member comprising two biasing parts bent-overfrom one of the folds thereof and biasing said two contact parts towardeach other whereby when said two separate line terminals are connectedto a common generally rigid conducting stab said two biasing partsprovide contact pressure between each of said two separate lineterminals and the conducting stab, and said spring member and said twoseparate line terminals being supported for a limited amount of unitarymovement within said recess wherebv said two separate line terminals canalign with said conducting stab when said circuit breaker is connectedto said conducting stab.

9. A double-type circuit breaker comprising an insulating housingcomprising two adjacent insulating compartments, a separatecircuit-breaker mechanism supported in each of said compartments, eachof said mechanisms comprising a stationary contact and a movable contactcooperable with the stationary contact to open and close an electriccircuit, said insulating housing having a recess therein at one endthereof, two

separate line terminal members and a unitary spring member disposedgenerally within said recess, each of said two separate line terminalmembers comprising a generally flat planar support part, a generallyfiat planar contact part extending generally normal to the plane of thesupport part and a generally flat planar contact carrying part extendinggenerally normal to the planes of both the support part and the contactpart, each of said contact carrying parts supporting .a different one ofsaid stationary contacts, said unitary spring member comprising asheet-metal type member folded over and engaging the opposite flatsurfaces of both of the support parts of said two separate line terminalmembers between the folds thereof to thereby support said two separateline terminal members, one of the folds of said spring member comprisingtwo bent-over biasing parts engaging said two contact parts of said twoseparate line terminal members to bias said contact parts toward eachother, and said spring member and said two separate line terminalmembers being supported for limited unitary movement within said recesswhereby when said circuit breaker is plugged onto a generally flat andgenerally rigid conducting stab said contact parts can align with theopposite flat surfaces of said conducting stab, and said biasing partsproviding contact pressure between said contact parts of said twoseparate line terminal structure members and the opposite flat surfacesof said conducting stab.

10. A circuit breaker comprising an insulating housing, a circuitbreaker mechanism supported within said housing, said mechanismcomprising a pair of contacts cooperable to open and close an electriccircuit, said housing having a recess therein at one end thereof, a lineterminal structure disposed generally within said recess, said lineterminal structure comprising two separate terminal members and aseparate spring member, means connecting at least one of said separateterminal members in electrical series with said pair of contacts, saidseparate spring member supporting said separate terminal members suchthat said separate spring member and said separate terminal members aremovable as a unit within the confines of said recess, and said separatespring member functioning independently of said housing to bias saidseparate terminal members toward each other.

11. A circuit breaker comprising an insulating housing, acircuit-breaker mechanism supported within said housing, said mechanismcomprising a pair of contacts cooperable to open and close an electriccircuit, said housing having a cavity therein at one end thereof, aterminal structure disposed generally within said cavity, said terminalstructure comprising two separate terminal members and a separateunitary spring member, means connecting at least one of said separateterminal members in electrical series with said pair of contacts, eachof said separate terminal members comprising a generally flat planarsupport part and a generally flat planar contact part extendinggenerally normal to the plane of the support part, said separate springmember engaging the opposite flat surfaces of the support parts of saidseparate terminal members to support said separate terminal members,said separate spring member comprising two biasing parts biasing saidtwo contact parts toward each other, said separate terminal members andseparate spring member being supported for limited unitary movementwithin the confines of said cavity whereby said contact parts can alignwith a conducting stab when said separate terminal members are pluggedonto a common conducting stab, and said separate spring membe operatingindependently of said housing to provide contact pressure between saidseparate terminal members and said conducting stab.

'12. A circuit breaker comprising an insulating housing, a circuitbreaker mechanism supported within said housing, said mechanismcomprising a stationary contact and a movable contact cooperable withthe stationary contact to open and close an electric circuit, saidhousing having a recess therein at one end thereof a terminal structuredisposed generally within said recess, said terminal structurecomprising two separate terminal members and a separate spring member,each of said separate terminal members comprising a generally flatsupport,

part, a generally flat contact part extending generally normal to thesupport part and a generally fiat additional part extending generallynormal to both the support part and the contact part, at least one ofsaid additional par-ts supporting said stationary cont-act, saidseparate spring member comprising a sheet-metal type member folded overand engaging the opposite flat surfaces of the support parts of said twoseparate terminal members between the folds thereof to thereby supportsaid two separate terminal members, one of the folds of said separatespring member comprising two bent-over biasing parts engaging said twocontact parts of said separate terminal members to bias said contactparts toward each other, said separate spring member and said separateterminal members being supported for limited unitary movement withinsaid recess whereby when said circuit breaker is plugged onto agenerally flat and generally rigid conducting stab said contact partscan align wit-h the opposite flat surfaces of said conducting stab, saidbiasing par-ts providing contact pressure between said contact parts ofsaid separate terminal members and the opposite fiat surfaces of saidconducting stab, and said contact pressure being effected independentlyof said insulating housing.

References Cited by the Examiner UNITED STATES PATENTS 2,922,004 1/ 1960Miller et al. 200116 X 2,953,650 9/1960 Johnson 200- 116 X 2,953,6619/1960 Hammerly et al. 200-116 X 3,095,524 6/ 1963 Leonard et al.200-116 X ROBERT K. SCI-IAEFER, Primary Examiner.

KATHLEEN H. CLAFPY, Examiner.

H. O. JONES, Assistant Examiner.

1. IN COMBINATION, TWO ADJACENT INSULATING COMPARTMENTS, CIRCUIT-BREAKERMECHANISM SUPPORTED IN EACH OF SAID COMPARTMENTS, EACH OF SAID MECHANISMCOMPRISING A STATIONARY CONTACT AND A MOVABLE CONTACT COOPERABLE WITHTHE STATIONARY CONTACT TO OPEN AND CLOSE AN ELECTRIC CIRCUIT, SAIDMECHANISMS BEING INDEPENDENTLY OPERABLE, A SEPARATE EXTERNALLYACCESSIBLE LOAD TERMINAL SUPPORTED AT ONE END OF EACH OF SAIDCOMPARTMENTS, A SEPARATE LINE TERMINAL DISPOSED AT THE OTHER END OF EACHOF SAID COMPARTMENTS, AND A SEPARATE UNITARY SPRING MEMBER BIASING SAIDSEPARATE LINE TERMINALS TOWARD EACH OTHER WHEREBY WHEN SAID SEPARATELINE TERMINALS ARE CONNECTED TO A COMMON CON-